1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device including an oxide semiconductor film and a display device including the semiconductor device.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, a method for driving any of them, and a method for manufacturing any of them.
In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A semiconductor element such as a transistor, a semiconductor circuit, an arithmetic device, and a memory device are each an embodiment of a semiconductor device. An imaging device, a display device, a liquid crystal display device, a light-emitting device, an electro-optical device, a power generation device (including a thin film solar cell, an organic thin film solar cell, and the like), and an electronic device may each include a semiconductor device.
2. Description of the Related Art
Attention has been focused on a technique for forming a transistor (a thin film transistor (TFT) or a field-effect transistor (FET)) using a semiconductor thin film formed over a substrate. The transistor is applied to a wide range of electronic devices such as an integrated circuit (IC) or an image device (display device). A silicon-based semiconductor material is widely known as a material for a semiconductor thin film applicable to the transistor. As other materials, an oxide semiconductor has been attracting attention.
A highly reliable semiconductor device in which a transistor including an oxide semiconductor has stable electric characteristics is disclosed (for example, see Patent Document 1). In the semiconductor device, oxide semiconductor films with different compositions are stacked such that an oxide semiconductor film containing a large amount of In is positioned on the channel side and an oxide semiconductor film containing a large amount of a stabilizer such as Ga is positioned on the back channel side.